Mention of the Parthenon marbles hung like some invisible miasma over the debate. Photograph: British Museum

An extraordinary thing happened in the birthplace of democracy this week. Two men, both called Jonathan, both British and both senior mandarins at the British Museum, attended a conference held, propitiously, in the New Acropolis Museum.

On the surface, the two-day Unesco event was convened to discuss the hot topic of the restitution of cultural objects to their countries of origin. In this vein, success stories in the exchange of cultural property - from Italy's return of the Axum Obelisk to Ethiopia, to Germany's handing to Harare of the Stone Birds of Great Zimbabwe - were debated. But given the meeting's venue at the foot of a monument that has spawned more argument than any other single piece of separated art, it was perhaps inevitable that it would also be heavy in symbolism. The very presence of the two Jonathans in Athens did much to contribute to it.

For this was the first time that two prominent members from the staff of the British Museum - Jonathan King is keeper of the Department of Africa, Oceania and the Americas, Jonathan Williams, the keeper of the Department of Pre-history and Europe - have participated in a major cultural event in Greece. Let alone one where mention of the Parthenon marbles hung like some invisible miasma over the debate.

With so much bad blood between Athens and London on the ever-controversial issue of the repatriation of Elgin's loot, their attendance has got many wondering whether the cold war is becoming less chilly. King's agreement to speak on the matter of the British Museum's return on long-term loan of the ceremonial Mask of the Kwakwaka'waka First people of Vancouver Island, Canada, has helped reinforce the sense that a palpable thaw in relations has begun.

"It's significant because it shows that the British Museum is actively engaging in the question of return in a way that it would never have done, say, two years ago," Maurice Davies, deputy director of the Museums Association told me during the conference. "The British Museum has moved from a position of 'nothing will leave' to talking about cooperation and long-term loans. It's a phenomenal change."

The shift, less than six months before the resplendent New Acropolis Museum opens its doors to the public, has lighted a spark of optimism among those who have stalwartly campaigned for the marbles' return from Bloomsbury.

With cooperation rather than ownership being the name of the game - and restitution requests seemingly growing by the day as societies and economies turn increasingly to culture as an identity maker - one has to ask whether the winds of change are finally blowing through the corridors of the British Museum.

Of course, given that this is an argument that has moved in millimetres since Melina Mercouri, the late Greek actress cum culture minister who first raised the issue of the sculptures return at a Unesco conference in 1982, cognoscenti believe that it's the small steps that count.

Tellingly, with Pericles' iconic monument in their gaze, those who attended the Athens conference (bar perhaps the two Jonathans) gave their "blessing" to the hope that one day the Parthenon marbles will be released from the custody of the British Museum.

It remains to be seen how London will react when the New Acropolis Museum does open - and how Athens will fill in the gaps when it finally displays the world's most beautiful classical frieze within view of the temple it once adorned.